The present invention generally relates to an assembly comprising a remote sensor interface and a plurality of selectable two-way wireless communication devices, and, in particular, to a method and assembly for selecting one of a plurality of two-way wireless communication devices on the basis of one or more wake-up receivers.
RSIs are utilized for remotely collecting data in the field and communicating the collected data to one or more centralized locations. For example, RSIs are utilized in tracking and/or monitoring assets that are stored and/or transported in association with wireless transceivers, such as radio frequency identification tags (RFIDs). In such implementations, such as those described in U.S. Patent Application Publication No. 2005/0093702 A1, an RSI has sometimes been previously referred to as a “wireless reader tag” or “WRT.” The data regarding the tracked and/or monitored assets is communicated by an RSI to one or more central servers for processing. Such data is useful, for instance, in supply chain management. Such data further is useful, for instance, in homeland security, especially when the assets being tracked and/or monitored are being imported into the United States from foreign countries.
Of course, the RSIs of the present invention are preferably capable of wireless communications with external devices. For example, the RSI preferably communicates with other RSIs in forming one or more wireless networks. Furthermore, the RSI preferably communicates with a gateway that itself serves as a bridge to other networks, such as the Internet, a cellular network, or a Satellite network.
Unfortunately, wireless communications in urban environments can pose difficult and unpredictable challenges. Signal fading, multi-path transmission routes and reflections, environmental conditions, and other complications can cause radio signal degradations to occur thereby impairing radio communications. Low signal strengths, cancellations, and attenuations as signals propagate through construction materials impair signal reception by a wireless device. The US military has called for initiatives to address these issues due to problems experienced in urban combat environments.
One approach to solving some of these problems is to utilize a plurality of wireless communication devices arrayed to maximize the possibility that at least one of the devices is able to maintain wireless communication with a gateway, another device, or the like. Such an approach may be enhanced using, for example, high gain directional antennas arranged to provide overlapping patterns of coverage. Unfortunately, devoting multiple radios or other wireless communication devices to a single RSI results in considerably greater power consumption, among other problems. Power consumption could be reduced, however, if the RSI could select an individual radio for carrying out wireless communications on behalf of the RSI based on strength of signal and other criteria, and could hold radios in a standby mode when signals not directed specifically to that RSI are received. Thus, a need exists for a system and method for selecting one of a plurality of two-way wireless communication devices, particularly for use by an RSI in carrying out wireless communications, on the basis of determinations made by one or more wake-up receivers.